Free-standing metallic article for semiconductors

Abstract

A free-standing metallic article, and method of making, is disclosed in which the metallic article is electroformed on an electrically conductive mandrel. The mandrel has an outer surface with a preformed pattern, wherein at least a portion of the metallic article is formed in the preformed pattern. The metallic article is separated from the electrically conductive mandrel, which forms a free-standing metallic article that may be coupled with the surface of a semiconductor material for a photovoltaic cell.

What is claimed is: 
     
       1. A method of forming a photovoltaic cell, the method comprising the steps of:
 i) electroforming a metallic article on an electrically conductive mandrel, wherein the electrically conductive mandrel has an outer surface comprising at least one preformed pattern, wherein at least a portion of the metallic article is formed in the preformed pattern; 
 ii) separating the metallic article from the electrically conductive mandrel to form a free-standing metallic article; and 
 iii) electrically coupling the free-standing metallic article with a semiconductor material for a photovoltaic cell. 
 
     
     
       2. The method of  claim 1 , wherein the preformed pattern has a height and a width, wherein the ratio of the height to the width defines an aspect ratio, wherein the aspect ratio is greater than 1, and wherein the free-standing metallic article has a pattern substantially similar to the preformed pattern of the electrically conductive mandrel. 
     
     
       3. The method of  claim 1 , wherein the method further comprises the step of applying a coating metal on the free-standing metallic article. 
     
     
       4. The method of  claim 3 , wherein the metallic article comprises copper, and wherein the coating metal comprises nickel. 
     
     
       5. The method of  claim 1 , wherein the method further comprises the step of applying an attachment mechanism to the free-standing metallic article, wherein the attachment mechanism comprises a solder or a reactive metal. 
     
     
       6. The method of  claim 5 , wherein the reactive metal is a fire-through silver paste. 
     
     
       7. The method of  claim 5 , wherein the attachment mechanism is applied to a bottom surface of the free-standing metallic article. 
     
     
       8. The method of  claim 5 , wherein the semiconductor comprises an outer surface layer, and wherein the step of electrically coupling the free-standing metallic article comprises:
 coupling the attachment mechanism of the free-standing metallic article to the outer surface layer of the semiconductor; and 
 heating the attachment mechanism. 
 
     
     
       9. The method of  claim 8 , wherein the attachment mechanism is a reactive metal, and wherein the step of heating the attachment mechanism comprises heating to a temperature greater than or equal to about 400° C. 
     
     
       10. The method of  claim 1 , wherein the semiconductor comprises an outer surface layer, wherein the outer surface layer is an antireflective surface coating on a surface of the semiconductor material, and wherein the step of electrically coupling the free-standing metallic article comprises electrically coupling the free-standing metallic article to the semiconductor material through the antireflective surface coating. 
     
     
       11. The method of  claim 1 , further comprising the step of forming a photovoltaic cell, wherein the step of forming a photovoltaic cell comprises forming an antireflective surface coating on the photovoltaic cell, and wherein the free-standing metallic article is located between the semiconductor surface and antireflective surface coating. 
     
     
       12. The method of  claim 1 , wherein the semiconductor comprises an outer surface layer, wherein the outer surface layer is a transparent conductive oxide layer on a surface of the semiconductor material, and wherein the step of electrically coupling the free-standing metallic article comprises electrically coupling the free-standing metallic article to the transparent conductive oxide layer. 
     
     
       13. The method of  claim 12 , wherein the free-standing metallic article comprises a solder layer applied to a bottom surface of the free-standing metallic article, and wherein the step of electrically coupling the free-standing metallic article comprises adhering the solder layer to the transparent conductive oxide layer. 
     
     
       14. The method of  claim 1 , wherein a back surface of the semiconductor material comprises a plurality of first regions comprising a p-type dopant and a plurality of second regions comprising a n-type dopant, and wherein the step of electrically coupling the free-standing metallic articles comprises placing a first free-standing metallic article in contact with at least one of the first regions and placing a second free-standing metallic article in contact with at least one of the second regions. 
     
     
       15. The method of  claim 1 , wherein the metallic article comprises a plurality of substantially parallel first elements intersecting a plurality of substantially parallel second elements. 
     
     
       16. The method of  claim 1 , wherein the metallic article comprises a continuous grid pattern configured to serve as an electrical conduit within the photovoltaic cell. 
     
     
       17. The method of  claim 16 , wherein the continuous grid pattern includes a plurality of electroformed elements, and wherein the electroformed elements are integral with each other. 
     
     
       18. The method of  claim 1 , further comprising the step of forming the photovoltaic cell from the semiconductor material and the free-standing metallic article. 
     
     
       19. The method of  claim 1 , wherein the semiconductor material comprises a conductive metal layer on at least a portion of a surface of the semiconductor material, the conductive metal layer being electrically coupled to the surface;
 wherein the step of electrically coupling comprises electrically coupling the free-standing metallic article with at least a portion of the conductive metal layer, wherein the coupling of the free-standing metallic article forms a masked region of the conductive metal layer and an exposed region of the conductive metal layer, wherein the masked region is directly beneath the free-standing metallic article; and 
 wherein the method further comprises the step of removing at least a portion of the exposed region of the conductive metal layer to form a pattern in the conductive metal layer, the pattern being determined by the free-standing metallic article. 
 
     
     
       20. The method of  claim 19 , wherein the surface of the semiconductor material is a light incident top surface. 
     
     
       21. The method of  claim 19 , wherein the conductive metal layer comprises titanium, nickel, tungsten, chromium, molybdenum, or combinations thereof. 
     
     
       22. The method of  claim 19 , wherein the step of electrically coupling the free-standing metallic article comprises adhering the free-standing metallic article to at least a portion of the conductive metal layer. 
     
     
       23. The method of  claim 19 , wherein the step of removing at least a portion of the exposed region comprises removing all of the exposed region from the surface of the semiconductor material. 
     
     
       24. The method of  claim 19 , wherein the step of removing at least a portion of the exposed region comprises etching at least a portion of the exposed region from the surface of the semiconductor material. 
     
     
       25. A method for forming a photovoltaic cell, the method comprising the steps of:
 i) electroforming a metallic article on an electrically conductive mandrel, wherein the electrically conductive mandrel has an outer surface comprising at least one preformed pattern, wherein the metallic article comprises a plurality of substantially parallel first segments intersecting a plurality of substantially parallel second segments, wherein the plurality of substantially parallel first segments and the plurality of substantially parallel second segments have a height and a width, wherein the ratio of the height to the width defines an aspect ratio, and wherein a majority of the plurality of substantially parallel first segments and the plurality of substantially parallel second segments have an aspect ratio greater than 1; 
 ii) removing the metallic article from the electrically conductive mandrel, wherein the removed metallic article is a free-standing metallic article; 
 iii) electrically coupling the free-standing metallic article with a semiconductor material; and 
 iv) forming the photovoltaic cell from the semiconductor material and the free-standing metallic article. 
 
     
     
       26. The method of  claim 25 , wherein the metallic article comprises copper, and wherein a coating comprising nickel is applied on at least a portion of the metallic article. 
     
     
       27. The method of  claim 25 , further comprising the step of applying an attachment mechanism to the free-standing metallic article, wherein the attachment mechanism comprises a solder or a reactive metal; and
 wherein the step of electrically coupling the free-standing metallic article comprises:
 coupling the attachment mechanism of the free-standing metallic article with the semiconductor; and 
 heating the attachment mechanism. 
 
 
     
     
       28. The method of  claim 25 , wherein the step of forming a photovoltaic cell comprises:
 coupling a transparent layer to the surface of the semiconductor material, wherein the transparent layer comprises a dielectric antireflective surface coating or a conductive antireflective surface coating; and 
 coupling the free-standing metallic article to the transparent layer. 
 
     
     
       29. The method of  claim 25 , wherein the plurality of substantially parallel first segments and the plurality of substantially parallel second segment are linear and have a substantially rectangular cross-sectional shape. 
     
     
       30. The method of  claim 25 , wherein the plurality of substantially parallel first segments and the plurality of substantially parallel second segment are integral with each other.